This program covers the long standing development of laser microsurgical techniques which initially centered on ophthalmological applicaitons and new systems of interest in that field (Pulsed Carbon Dioxide lasers and pulsed ND:YAG slit lamp-based laser systems). Its primary focus for the last 3 years has been in cardiological application of lasers, in particular laser angioplasty. In order to develop new laser microsurigal techniques in this new field, it was necessary to analyse a variety of laser sources and their tissue effects and the feasibility of transmission through flexible fiber optics. New sources such as Erbium:YAG (YLF) lasers coupled to zirconium flouride optical fibers and excimer lasers coupled to fused silica fibers were examined as well as more conventional sources (pulsed carbon dioxide and Nd:YAG lasers, and continuous wave argon and dye lasers). In collaboration with the Naval Research Lab, we have developed the new eribium laser microsurgery technology through feasability studies to the development of the initial microsurigal prototype using zirconium fluoride fibers. Refinement of this system is primarily directed towards intravascular ablation (laser angioplasty) but include application to intraocular surgery (particularly vitreal and corneal transplantation), destruction of renal stones, and endoscopic microsurgery. Parallel development of excimer microsurgery has evaluated state-of-the-art technology and provided a research microsurgical system for in vivo studies.